1. Field of the Invention
The present invention relates to a printing apparatus capable of printing an image on paper such as an envelope, a control method therefor, and a storage medium.
2. Description of the Related Art
An image forming apparatus (printing apparatus) includes one or more paper containing units (sheet holding unit). The image forming apparatus feeds sheets contained in the paper containing unit one by one, and forms (prints) an image on the fed sheet. The size of paper contained in each paper containing unit can be set. For example, standard-sizes such as A4 and B4, and an arbitrary size such as 210 mm×290 mm can be set.
As a special standard-size, an envelope size can also be set. Paper with a projection such as the projecting piece, that is, margin (to be referred to as a flap hereinafter) of an envelope or the index portion of index paper is set so that the flap serves as the trailing end in the sub-scanning direction. With this setting, a paper area up to the flap is handled as a standard-size, and printing is performed. Also, there is known a technique of setting an envelope so that its flap is positioned in the sub-scanning direction, recognizing a flap position by a sensor when the envelope is conveyed, and suppressing image misregistration (see Japanese Patent Laid-Open No. 9-109492).
Paper longer in the sub-scanning direction than in the main-scanning direction, like an envelope, takes a long printing time when the long edge is made parallel to the conveyance direction and printing is performed (short-edge feed). The time necessary to print can be shortened by setting an envelope so that its flap comes to the end in the main-scanning direction, making the short edge of the envelope parallel to the conveyance direction, and printing (long-edge feed). In this case, an image needs to be shifted by the flap width and printed. However, since the flap width differs between envelope manufacturers, the user needs to enter a flap width, putting a burden on him.